Directional electrostatic speaker assembly



. 8, 1959 J. P. KUEHN DIRECTIONAL ELECTROSTATIC SPEAKER ASSEMBLY FiledOct. 18, 1956 1 l E g INVENTOR. John P Aue/m Afforneys United. StatesPatent DIRECTIONAL ELECTROSTATIC SPEAKER ASSEMBLY John P. Kuehn,Huntington, N.Y., assignor to Pickering Associates, Inc, Oceanside,N.Y., a corporation of New York Application October 18, 1956, Serial No.616,741

1 Claim. (Cl. 179-147).

. .suitable material.

fixed plate to form a condenser. Variations in the output 7 wave in theelectrical system will cause the diaphragm to move in synchronismtherewith, thereby establishing a sound wave.

When an electrostatic speaker is utilized the sound radiation is highlydirective. This is especially so at the higher frequencies. And in thosesystems employing a low frequency speaker and a high frequencyelectrostatic speaker, it is often diflicult to direct the sound wavesof the high frequency speaker for maximum enjoyment.

In systems where an electrostatic spaker is employed .the direction ofthe sound waves with respect to the physical position of the listenercan have a large effect on the enjoyment resulting to the listener.Also, many persons find greater listening pleasure when they can directthe sound waves in order to take maximum advantage of the acoustics inthe room. Often listeners employ more than one speaker and desire todirect the sound waves from the various speakers in such manner that thesound waves cooperate and complement one another.

In order to properly direct the sound waves, an electrostatic speakermust be designed so that the highly directional characteristics of thewaves can be utilized to give maximum enjoyment to the listener andavoid undesirable results.

The invention herein disclosed has as its main object the provision of adirectional electrostatic speaker with which highly directional soundwaves can be properly distributed and dispersed.

Another object of this invention is to provide a directionalelectrostatic speaker with which sound waves can be directed inconformity with the physical position of the listener and the roomarchitecture.

A further object of the invention is to provide a directionalelectrostatic speaker assembly which utilizes few parts and requires aminimum amount of time and effort to manufacture and assemble.

The construction of the directional electrostatic speaker is describedherein with reference to the drawings, in which:

Fig. l is a front elevational view of a directional electrostaticspeaker constructed in accordance with the teachings of this inventionwith a portion thereof shown in section;

Fig. 2 is a front perspective view of the speaker shown in Fig. 1 withthe speaker slightly pivoted about a horizontal axis;

Fig. 3 is a partially sectional elevation taken along the line 3-3 inthe direction of the arrows indicated in Fig. 1; and

, 2,916,562 7 Patented Dec. 8, 1959 ice Fig. 4 is a side view of theelectrostatic speaker shown in Fig. 1 with the speaker pivoted slightlyabout its horizontal axis and a portion thereof shown in section.

The speaker shown in the figures consists of a plastic frame composed ofarcuate top and bottom segments designated by the numerals 10 and 11,respectively. These segments are identical and joined by elongated sidemembers 12 and 13 which are of rectangular crosssection and alsoconstructed of plastic material. As seen in the figures, one end ofmember 10 and one end of ;member 11 are joined by member 12 and theremaining ends of members 10 and 11 are joined by member 13.

It should be noted that although members 10, 11, 12 and 13 have beendescribed as plastic members, they can be constructed or formed fromwood or any other Screen 14, which is seen in Fig. 4, is one of twoidentical acoustically transparent metal screens 14 and 15. Thesescreens are preferably made of woven galvaniz ed iron wire.

Each of the screens is flocked with fibers of cotton, rayon, fiber glassor other dielectric material. The flocking on screen 14 is designatedgenerally as 16 while the flocking on screen 15 is designated generallyas 17. Acoustical element 18 is maintained in position between theflocking 16 and 17. This acoustical element can be any diaphragm whichis suitable for this purpose and the precise manner in which diaphragm18, the flocking and the transparent screens are mounted is describedand claimed in a co-pending application, Serial No.

545,875, entitled Electrostatic Speaker, which was filed inthe UnitedStates Patent Office on November 9, 1955 and which is assigned to thesame assignee as is this application.

/ shown.

My invention resides in the shape of the speaker as '1 determined by thearcuate segments and the assembling .or mounting of the same to a base.

As seen in the figures, the external appearance of the speaker is suchthat its front is convex while its rear is concave.

The convex front which is designated as 19a, serves to radiate the soundwaves or disperse them in a plane perpendicular to pillar 21 whichextends upward through bottom segment 11 and which is rigidly connectedat its end to top segment 10. Pillar 21 is cylindrical member having anaxial internal cylindrical opening throughout its length. An identicalpillar 22 extends parallel to pillar 21 through segment 11 and isconnected to the top segment at the other end of the speaker.

Pillars 21 and 22 serve to support the speaker above an underlyingsurface as shown. Also a swivel mounting is employed which connectsthese pillars to base 23, which is a wooden rectangular member. The basemember can be any configuration or material desired. An end of pillar 21is shown in Fig. 3 where a detailed view of the swivel mounting is alsoshown.

Sleeve 24 is attached to the lower end of pillar 21. Sleeve 24 is also acylindrically hollow member and has a large opening 25 with an internaldiameter approximately equal to the external diameter of pillar 21 andis mounted thereon in a press fit. Opening 25 projects into a smallerdiameter opening 26 which has an internal diameter approximately equalto the internal diameter of the opening in pillar 21. The portion ofsleeve 24 through which the smaller diameter hollow extends isexternally threaded at 26a.

Spring housing 27 has cylindrical openings of various diametersextending therethrough and oneend of member 27 is internally threaded at27a so that member 27 can be joined with sleeve 24 by cooperation ofthreads 26a and 27a. A portion of the hollow within member 27 is formedto enclose helical compression spring 28, which sets within. The springas mounted yieldingly urges ball seat 29 downwardly against ball 30,which is attached to base 23 by means of externally threaded tail 31,which passes through the base and is fastened thereto by nut 32. As seenin Fig. 3, a portion of the base is recessed so that nut 32 will notinterfere with the surface upon which base 23 is placed.

Ball seat 29 which is a washer-like member has a cylindrical openingextending therethrough and rests atop ball 30. Adjustment member 33 hasa ball seat portion 34 formed therein which encompasses the lowerperiphery of ball 30 and an upper internally threaded portion 33a whichcan cooperate with external threads 27b at the lower end of springhousing 27.

As pointed out above, each of the members which cooperates to maintainpillar 21 in attachment with base 23 has a cylindrical opening extendingtherethrough. The purpose of this is to enable cable 34 to extend upwardly into the speaker for attachment with the diaphragm or acousticalelement. The other end of cable 34 which is not shown is attached to theoutput of the electrical system of the device. Pillar 22 is maintainedin attachment with base 23 in the same manner as is pillar 21.

As shown in Fig. 3, pillar 21 is free to rotate about any horizontalaxis through ball 30. Likewise, pillar 22 is free to rotate about anyhorizontal axis through the ball associated with it. However, sincepillars 21 and 22 are connected to rigid bottom segment 11, they arerestricted to rotation about the single horizontal axis which passesthrough the balls associated with them. An imaginary horizontal axis ofrotation is shown as the line XX in Fig. 2.

The front of the speaker as mentioned before is convex. Therefore, soundradiating therefrom is dispersed in a plane which is parallel to thevertical axis of the front of the speaker. This axis is shown in Fig. 2as the line Y-Y.

Utilizing the swivel mountings of pillars 21 and 22 the sound wavesradiating from the speaker can be directed in a vertical plane about theaxis XX so that with my speaker sound waves are dispersed in ahorizontal plane perpendicular to the vertical plane of the speakerbecause of the convex configuration of the front of the speaker and canbe dispersed in a vertical plane perpendicular to the axis of rotationof pillars 21 and 22.

The speaker is shown in Fig. 2 pivoted slightly for!- ward so that thesound radiating therefrom is directed downwardly as well as radially. Aside View of the speaker in substantially the same position is shown inFig. 4.

Adjustment member 33 when threaded upon spring housing 27 appliesfriction force between ball 30 and ball seat 29 due to the force ofspring 28 so that the pillar associated therewith is maintained inposition and thus allows the speaker to be maintained in position at anangle about the XX axis. With this assembly, the electrostatic speakercan be adjusted about the horizontal axis and maintained in the positiondesired.

Also, since ball and socket joints are used, aligning problems inassembly are greatly reduced.

Thus, among others, the several objects of the invention as specificallyaforenoted are achieved. Obviously, numerous changes in construction andrearrangement of parts may be resorted to without departing from thespirit of the invention as defined by the claim.

I claim:

A directional electrostatic speaker assembly including in combination anacoustical member, a front surface of said acoustical member convexabout a vertical axis, a rear surface of said acoustical member concaveabout a vertical axis, a rigid bottom surface of said acoustical member,a flat base, a support member rigidly connected at one end to saidbottom surface and perpendicular thereto, a second support member spacedfrom said first support member and rigidly connected at one end to saidbottom surface and perpendicular thereto, a pivotal connection of theremaining end of said first support member to said base, a secondpivotal connection of the remaining end of said second support member tosaid base, a; axis of rotation formed by the pivotal connections of saidsupport members, said rigid members spaced from one another and parallelwith one another for rotation about said axis of rotation whereby theposition of said acoustical element with respect to said base can bechanged solely by rotation of said support members about said axis andmeans associated with each of said pivotal connections for maintainingits respective support membe in a fixed position.

References Cited in the file of this patent UNITED STATES PATENTS980,774 Halle Ian. 3, 1911 1,110,973 Tischler Sept. 15, 1914 1,789,554Kyle Ian. 20, 1931 2,682,580 Chin et al. June 29, 1954 2,824,178 BobbFeb. 18, 1958 FOREIGN PATENTS 695,042 France Sept. 23, 1930

